Your profile says you have the Archos 7, which doesn't have full access to the market. You can try and browse the link below and download our app center and download using that, though you might have to allow access to third party apps (Settings > Applications > Check the mark next to unknown sources)

ok thank you very much for the help i will have a look. Another thing every time i go to search in the app store everything i type it says it cannot find it when i just seen the app when i was going through the list? how come it does that?regards tamara

If it is an Archos product, you're running Appslib, and I don't know enough about it to troubleshoot. What you can do is go to the website below and install the latest version, maybe there are some fixes: